Nationals 5, Rockies 1: Jordan Zimmermann worked eight strong innings and Ian Desmond homered for the second straight game as host Washington spoiled Roy Oswalt’s debut with Colorado.

Zimmermann (10-3) continued to dominate at home, allowing one unearned run on six hits while striking out nine with one walk. The right-hander retired 16 in a row at one point and improved to 7-0 with a 0.92 ERA in eight home starts for the Nationals, who pulled back to .500 at 36-36.

Desmond gave Washington an early lead with a solo homer in the second off Oswalt (0-1), who struck out 11 over five innings in his first start since last Aug. 23 with Texas. Oswalt allowed four runs on nine hits for the Rockies, who have lost the first four games of their nine-game road trip.

The Nationals added a run in the fourth on Kurt Suzuki’s RBI single, and Adam LaRoche tripled in two runs in the fifth before Steve Lombardozzi scored on Zimmermann’s sacrifice fly in the sixth. LaRoche went 3-for-4 for his first three-hit game of the season.

Colorado brought the tying run to the plate with one out in the eighth after DJ LeMahieu singled in a run, but Zimmermann struck out Carlos Gonzalez and Michael Cuddyer to end the inning.

GAME NOTEBOOK: Zimmermann is the first Washington pitcher to earn 10 wins by June 20 since Livan Hernandez in 2005. … Rockies RF Michael Cuddyer singled in the first inning to extend his career-high hitting streak to 18 games. …The Nationals have hit at least one home run in 81 consecutive series.